JPH10273327A - Production of ruthenium tetraoxide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily produce ruthenium tetraoxide without causing the problems of the generation and removal of by-products by oxidizing ruthenium metal or a specific ruthenium compound with ozone. SOLUTION: A ruthenium compound selected from ruthenium metal, ruthenium metal/carrier, ruthenium dioxide, a ruthenium trihalide, ruthenium sulfate and a ruthenium complex is dissolved in water, a solvent stable to ruthenium tetraoxide, ozone and oxygen used as an oxidizing agent or a mixed solvent stable to water and oxidizing agent. Ozone/air or ozone/oxygen generated by an ozonizer is passed through the solution under stirring and the ruthenium compound is oxidized at pH <=10, preferably <=9, more preferably <=7 and 0-100 deg.C, preferably 5-50 deg.C to obtain ruthenium tetraoxide. The produced ruthenium tetraoxide has high purity and is obtained in the form of an aqueous solution or a mixed solution stable to ruthenium tetraoxide, ozone and oxygen used as an oxidizing agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing ruthenium tetroxide. More specifically, the present invention relates to a method for producing ruthenium tetroxide by oxidizing a ruthenium compound with ozone. Ruthenium tetroxide obtained according to the present invention is utilized as a versatile oxidizing agent for organic compounds.

[0002]

2. Description of the Related Art Conventionally, various methods for producing ruthenium tetroxide have been known. For example, a method of oxidizing potassium ruthenate with chlorine (JLHow et al., J. Am. Chem. Soc.,
23,775 (1901).), A method of oxidizing ruthenium sulfate with potassium permanganate (EC Robert et al., J. Am. Chem. Soc.,
74,5012 (1952).), A method of oxidizing ruthenium dioxide or ruthenium trichloride with sodium periodate (J. Ca
puto et al., Tetrahedron Letter, 4729 (1967).), a method of oxidizing ruthenium trichloride with sodium bromate (LM
Berkowitz et al., J. Am. Chem. Soc., 80, 6682 (1958), a method of oxidizing ruthenium trichloride with sodium hypochlorite (S. Wolfe et al., J. Chem. Soc. D. 1420 (1970).), A method of oxidizing ruthenium trichloride or ruthenium dioxide with a peracid such as peracetic acid (US Pat. No. 3,997,578), and a method of oxidizing ruthenium trichloride with a persulfate (M. Schroder et al., J. Che
m. Soc. Chem. Comun., 58 (1978).), a method of oxidizing ruthenium trichloride with ceric sulfate (S. Gidding et al.,
J. Org. Chem., 53, 1103 (1988).), A method of oxidizing ruthenium trichloride with potassium ferricyanide (LPSingh et a
l., J. Indian Chem. Soc., 58, 1204 (1981)).

[0003] However, in the method of oxidizing potassium ruthenate with chlorine, the method of oxidizing potassium chloride with ruthenium sulfate with potassium permanganate always produces by-produced manganese oxide in an equivalent amount or more. In the method of oxidizing ruthenium oxide or ruthenium trichloride with sodium periodate, sodium bromate or sodium hypochlorite,
Salts such as sodium iodate, sodium bromide and sodium chloride are always by-produced in equal amounts or more. Further, even in the method of oxidizing with a peracid such as peracetic acid, an acid in an equal amount or more is always produced as a by-product.
Further, even in the method of oxidizing with persulfate, ceric sulfate, and potassium ferricyanide, equal amounts or more of sulfate, cerous sulfate, and potassium ferrocyanide are always produced as by-products. Therefore, in the conventional method, generation of by-products after the reaction
There was a problem of removal, and it was not suitable as an industrial production method.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and easily converts ruthenium tetroxide, which is useful as an oxidizing agent, without generating or removing by-products. It is to provide an industrial method that can be manufactured.

[0005]

Means for Solving the Problems The present inventors have studied a method for producing ruthenium tetroxide having no problem of generation and removal of by-products, and as a result, have completed the present invention. That is, the present invention is an aqueous solvent, ruthenium tetroxide oxidizing agent,
A process for producing ruthenium tetroxide, characterized by using ozone as an oxidizing agent for a ruthenium compound in a solvent stable to ozone and oxygen or a mixed solvent stable to water and an oxidizing agent.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION As the ruthenium compound used in the present invention, ruthenium metal and various ruthenium compounds are used. Specific examples include ruthenium oxides such as ruthenium dioxide; ruthenium hydroxide; ruthenium sulfate; ruthenium halides such as ruthenium chloride and ruthenium bromide; and ruthenium complexes such as ruthenium dodecacarbonium. Further, a ruthenium metal support in which ruthenium metal is supported on various carriers can also be used. Specifically, ruthenium metal / alumina,
Ruthenium metal / carbon, ruthenium metal / silica alumina, ruthenium metal / titania and the like can be mentioned.

Ozone, which is an oxidizing agent for a ruthenium compound used in the present invention, is a method of performing silent discharge in clean dry air or oxygen (ozone generator: ozonizer), a method of irradiating ultraviolet rays to air or oxygen, a method of low temperature. For electrolysis of diluted sulfuric acid, a reaction between fluorine and water, and a chemical method for oxidizing phosphoric acid. Among these methods, the method using an ozone generator can easily obtain a large amount of ozone. Recently, it has been used on a large scale as a bactericide for clean drinking water and a wastewater treatment agent, and industrially. This is the most preferable method.

As a reaction solvent used in the present invention, an aqueous solvent, ruthenium tetroxide as an oxidizing agent, a solvent stable to ozone and oxygen, or a mixed solvent stable to water and an oxidizing agent are usually used. Specific examples of the solvent stable to the oxidizing agent include organic acids such as acetic acid; halogenated hydrocarbons such as carbon tetrachloride, chloroform and dichloromethane; methane-based saturated hydrocarbons such as pentane and hexane; cycloparaffin-based carbon such as cyclohexane. Hydrogen and the like. Among these solvents, organic acids, halogenated hydrocarbons and paraffin solvents are particularly preferred. In addition, when the mixed solvent becomes non-uniform with water, the reaction rate can be accelerated by sufficiently stirring.

The ruthenium tetroxide obtained in the present invention is found to be high purity ruthenium tetroxide by UV-visible spectroscopy. This ruthenium tetroxide is an aqueous solution,
It is obtained as a solution stable to ruthenium tetroxide as an oxidizing agent, ozone and oxygen, or a mixed solution stable to water and an oxidizing agent. For these solutions, the most suitable solution can be selected as the reaction solvent according to the ruthenium tetroxide oxidation reaction to be used.

In the method of the present invention, the ruthenium compound is usually mixed with an aqueous solvent, ruthenium tetroxide as an oxidizing agent, a solvent stable to ozone and oxygen, or a mixed solvent stable to water and an oxidizing agent while generating ozone while stirring. Ozone / air or ozone / oxygen generated by the vessel was ventilated, and the reaction temperature was 0
-100 ° C, preferably 5-50 ° C, and the pH of the reaction solution is 10
The reaction is carried out below, preferably below 9, more preferably below 7. The time required for the reaction varies depending on the reaction conditions such as the amount of the ruthenium compound, the ozone generation rate, the reaction temperature, and the pH of the reaction solution.

[0011]

Reference Examples and Embodiments Hereinafter, reference examples and embodiments will be described in detail. In Examples, an ozonizer SG-01A (manufactured by Sumitomo Precision Industries) was used as an ozone generator. The UV-visible absorption spectrum was measured using a Hitachi autograph spectrophotometer.
330 was used.

Reference Example 1 Water was placed in a 500 ml round bottom Pyrex flask equipped with a stirrer, thermometer, pH meter, condenser, and microburette.
ml, 46.8 mg (0.225 mmol) of ruthenium trichloride, and from the microburette with stirring at room temperature (about 20 ° C)
0.66 ml (0.603 mmol) of 6.8% sodium hypochlorite was added. The pH of the solution immediately before the addition of sodium hypochlorite is 3.
0, the color was black, but immediately after the addition, the pH was immediately
At 5.5, the color changed to yellow. The reaction was continued for 10 minutes, but there was no change in pH or color tone. After the completion of the reaction, the ultraviolet-visible absorption spectrum of the yellow reaction solution (200 to 60
0 nm). FIG. 1 shows the measured absorption spectrum. Table 1 shows the absorption wavelength (λ) and the molar extinction coefficient (ε). In addition, reference 1 of the ultraviolet-visible spectrum of ruthenium tetroxide (EC Robert et al., J. Am. Chem. Soc., 74,
5012 (1952).) Is shown in Table 1 and FIG. as a result,
Since the absorption spectrum of the ruthenium trichloride / sodium hypochlorite system was consistent with that of Reference 1, it was found that ruthenium tetroxide was generated.

Example 1 500 ml equipped with a stirrer, thermometer, pH meter and condenser
A round bottom Pyrex flask is charged with 300 ml of water and 46.8 mg (0.225 mmol) of ruthenium trichloride. While stirring at room temperature (about 20 ° C.), 0.112 g (2.3 mmol) / min of ozone from oxygen is added to this solution using an ozone generator. The gas generated at the speed of was introduced. The pH of the solution immediately before aeration was 3.0 and the color tone was black, but one minute after the aeration, the pH changed to 2.8 and the color tone changed to yellow. The reaction was continued for 10 minutes. After 10 minutes, the pH was 2.7 and the color was yellow. After the completion of the reaction, an ultraviolet-visible absorption spectrum (200 to 600 nm) of the yellow reaction solution was measured. The measured absorption spectrum is shown in FIG. Table 1 shows the absorption wavelength (λ) and the molar extinction coefficient (ε). As a result, the absorption spectrum of the ruthenium trichloride / ozone system was consistent with that in Reference Example 1 and Reference 1, indicating that ruthenium tetroxide was generated.

Example 2 Example 1 was repeated except that 30 mg (0.225 mmol) of ruthenium dioxide was used as the ruthenium compound in the same reactor as in Example 2.
And reacted exactly the same. The pH of the solution immediately before aeration is 5.
5, the color was black, but after 1 minute of ventilation, the pH was 4.9,
The color changed to yellow. The reaction was continued for 10 minutes. After 10 minutes, the pH was 4.7 and the color was yellow. After completion of the reaction, the ultraviolet-visible absorption spectrum of the yellow reaction solution (200 to 6
00 nm). As a result, the measured absorption spectrum was exactly the same as in Example 1. Table 1 shows the absorption wavelength (λ) and the molar extinction coefficient (ε). As a result, since the absorption spectrum of the ruthenium dioxide / ozone system was in agreement with Reference Example 1 and Reference 1, it was found that ruthenium tetroxide was generated.

Example 3 The reaction was carried out in the same manner as in Example 2 except that the pH of the reaction solution was maintained at 9 with 1N sodium hydroxide and ruthenium sulfate was used as the ruthenium compound. After the completion of the reaction, an ultraviolet-visible absorption spectrum (200 to 600 nm) of the yellow reaction solution was measured. As a result, the measured absorption spectrum was exactly the same as in Example 2. Absorption wavelength (λ) of the measured spectrum,
The molar extinction coefficient (ε) is shown in Table 1. As a result, since the absorption spectrum of the ruthenium sulfate / ozone system was in agreement with Reference Example 1 and Reference 1, it was found that ruthenium tetroxide was produced.

[0016]

[Table 1]

[0017]

According to the present invention, high-purity ruthenium tetroxide can be easily obtained without any problem of generation and removal of by-products.
It is suitable as an industrial method for producing ruthenium tetroxide.

[Brief description of the drawings]

FIG. 1 shows an ultraviolet-visible absorption spectrum of Reference Example 1.

FIG. 2 shows an ultraviolet-visible absorption spectrum of Example 1 (257 nm is absorption of ozone).

FIG. 3 is an ultraviolet-visible absorption spectrum of ruthenium tetroxide (Ru ⁺⁸ ), perruthenate (Ru ⁺⁷ ), and ruthenate (Ru ⁺⁶ ) of Literature 1.

Claims (2)

[Claims] 1. A method for producing ruthenium tetroxide, comprising oxidizing a ruthenium compound with ozone. 2. The process for producing ruthenium tetroxide according to claim 1, wherein the ruthenium compound is ruthenium metal, ruthenium metal / carrier, ruthenium dioxide, ruthenium trihalide, ruthenium sulfate or a ruthenium complex.